Characteristics of TB cases without documented sputum culture in the United States, 2011-2021.

Culture-based diagnostics are the gold standard for diagnosing pulmonary TB (PTB). We characterized culture practices by comparing cases with documented sputum culture to those without.Using multivariable logistic regression, we examined associations between PTB case characteristics and no documented sputum culture reported to the U.S. National TB Surveillance System during 2011-2021.Among 69,538 PTB cases analyzed, no sputum culture attempt was documented for 5,869 (8%). Non-sputum culture specimens were documented for 54%, 80%, and 89% of cases without documented sputum culture attempts among persons aged <15 years, 15-64, and 65+ years, respectively; bronchial fluid and lung tissue were common non-sputum specimens among cases in persons >15 years old. Having no documented sputum culture was associated with age <15 years (aOR 23.84, 99% CI 20.09-28.27) or ≥65 years (aOR 1.22, 99% CI 1.07-1.39), culture of a non-sputum specimen (aOR 6.57, 99% CI 5.93-7.28), residence in a long-term care facility (aOR 1.58, 99% CI 1.23-2.01), and receiving TB care outside of a health department (aOR 1.79, 99% CI 1.61-1.98).Inability to obtain sputum from children and higher diagnostic suspicion for disease processes that require tissue-based diagnostics could explain these findings..

Validity of age estimation methods and reproducibility of bone/dental maturity indices for chronological age estimation: a systematic review and meta-analysis of validation studies.

Several approaches have been developed to estimate age, an important aspect of forensics and orthodontics, using different measures and radiological examinations. Here, through meta-analysis, we determined the validity of age estimation methods and reproducibility of bone/dental maturity indices used for age estimation. The PubMed and Google Scholar databases were searched to December 31, 2021 for human cross-sectional studies meeting pre-defined PICOS criteria that simultaneously assessed the reproducibility and validity. Meta-estimates of validity (mean error: estimated age-chronological age) and intra- and inter-observer reproducibility (Cohen's kappa, intraclass correlation coefficient) and their predictive intervals (PI) were calculated using mixed-effect models when heterogeneity was high (I2 > 50%). The literature search identified 433 studies, and 23 met the inclusion criteria. The mean error meta-estimate (mixed effects model) was 0.08 years (95% CI - 0.12; 0.29) in males and 0.09 (95% CI - 0.12; 0.30) in females. The PI of each method spanned zero; of nine reported estimation methods, Cameriere's had the smallest (- 0.82; 0.47) and Haavikko's the largest (- 7.24; 4.57) PI. The reproducibility meta-estimate (fixed effects model) was 0.98 (95% CI 0.97; 1.00) for intra- and 0.99 (95% CI 0.98; 1.00) for inter-observer agreement. All methods were valid but with different levels of precision. The intra- and inter-observer reproducibility was high and homogeneous across studies.

From Silos to Solidarity: Case Study of a Patient-Centered, Integrative Approach to Opioid Tapering and Chronic Pain Mitigation in a Multidisciplinary AIDS Clinic.

BACKGROUND: People with HIV (PWH) are at a disproportionate risk for experiencing both chronic pain and opioid use disorder (OUD). Prescription opioid tapering is typically addressed within the "silo model" of medical care, whereby attention is focused solely on opioid addiction rather than also addressing chronic pain management, and limited communication occurs between patient and providers. OBJECTIVE: This descriptive case study examined an integrative, collaborative care model consisting of Provider, Physical Therapist (PT), and Patient aimed at decreasing chronic pain and opioid use within a multidisciplinary HIV/AIDS clinic. METHOD: A physical-therapy based model of chronic pain mitigation and physician-driven opioid tapering was implemented. The Provider, PT, and Patient worked collaboratively to address physiological pain, pain coping skills and opioid tapering. A patient case example was used to illustrate the implementation of the model for a future, larger study in the same patient population. RESULTS: This model was feasible in this case example in terms of clinic workflow and acceptability to both the Patient and Providers in this clinic. After the intervention, the Patient's pain was fully eliminated, and he had ceased all opioid use. CONCLUSION: Results of this case study suggest that utilizing an integrative, patient-centered approach to both chronic pain management and opioid tapering may be feasible within the context of a multidisciplinary HIV/AIDS clinic. Generalizability is limited by case study model; however, this gives insight into the value of a collaborative alternative compared to a "silo" model of opioid tapering and chronic pain management in preparation for a larger study.

A nurse-led intervention to improve management of virological failure in public sector HIV clinics in Durban, South Africa: A pre- and post-implementation evaluation.

BACKGROUND: Identification of patients on antiretroviral therapy (ART) with virological failure (VF) and the response in the public health sector remain significant challenges. We previously reported improvement in routine viral load (VL) monitoring after ART commencement through a health system-strengthening, nurse-led 'VL champion' programme as part of a multidisciplinary team in three public sector clinics in Durban, South Africa. OBJECTIVES: To report on the impact of the VL champion model adapted to identify, support and co-ordinate the management of individuals with VF on first-line ART in a setting with limited electronic-based record capacity. METHODS: We evaluated the VL champion model using a controlled before-after study design. A paper-based tool, the 'high VL register', was piloted under the supervision of the VL champion to improve data management, monitoring of counselling support, and enacting of clinical decisions. We abstracted chart and electronic data (TIER.net) for eligible individuals with VF in the year before and after implementation of the programme, and compared outcomes for individuals during these periods. Our primary outcome was successful completion of the VF pathway, defined as a repeat VL <1 000 copies/mL or a change to second-line ART within 6 months of VF. In a secondary analysis, we assessed the completion of each step in the pathway. RESULTS: We identified 60 and 56 individuals in the pre-intervention and post-intervention periods, respectively, with VF who met the inclusion criteria. Sociodemographic and clinical characteristics were similar between the periods. Repeat VL testing was completed in 61.7% and 57.8% of individuals in these two groups, respectively. We found no difference in the proportion achieving our primary outcome in the pre- and post-intervention periods: 11/60 (18.3%; 95% confidence interval (CI) 9 - 28) and 15/56 (22.8%; 95% CI 15 - 38), respectively (p=0.28). In multivariable logistic regression models adjusted for potential confounding factors, individuals in the post-intervention period had a non-significant doubling of the odds of achieving the primary outcome (adjusted odds ratio 2.07; 95% CI 0.75 - 5.72). However, there was no difference in the rates of completion of each step along the first-line VF cascade of care. CONCLUSIONS: This enhanced intervention to improve VF in the public sector using a paper-based data management system failed to achieve significant improvements in first-line VF management over the standard of care. In addition to interventions that better address patient-centred factors that contribute to VF, we believe that there are substantial limitations to and staffing requirements involved in the ongoing utilisation of a paper-based tool. A prioritisation is needed to further expand and upgrade the electronic medical record system with capabilities for prompting staff regarding patients with missed visits and critical laboratory results demonstrating VF.

A packaged intervention to improve viral load monitoring within a deeply rural health district of South Africa.

BACKGROUND: The KwaZulu-Natal (KZN) province of South Africa has the highest prevalence of HIV infection in the world. Viral load (VL) testing is a crucial tool for clinical and programmatic monitoring. Within uMkhanyakude district, VL suppression rates were 91% among patients with VL data; however, VL performance rates averaged only 38·7%. The objective of this study was to determine if enhanced clinic processes and community outreach could improve VL monitoring within this district. METHODS: A packaged intervention was implemented at three rural clinics in the setting of the KZN HIV AIDS Drug Resistance Surveillance Study. This included file hygiene, outreach, a VL register and documentation revisions. Chart audits were used to assess fidelity. Outcome measures included percentage VL performed and suppressed. Each rural clinic was matched with a peri-urban clinic for comparison before and after the start of each phase of the intervention. Monthly sample proportions were modelled using quasi-likelihood regression methods for over-dispersed binomial data. RESULTS: Mkuze and Jozini clinics increased VL performance overall from 33·9% and 35·3% to 75·8% and 72·4%, respectively which was significantly greater than the increases in the comparison clinics (RR 1·86 and 1·68, p < 0·01). VL suppression rates similarly increased overall by 39·3% and 36·2% (RR 1·84 and 1·70, p < 0·01). The Chart Intervention phase showed significant increases in fidelity 16 months after implementation. CONCLUSIONS: The packaged intervention improved VL performance and suppression rates overall but was significant in Mkuze and Jozini. Larger sustained efforts will be needed to have a similar impact throughout the province.

Comparative analyses of published cost effectiveness models highlight critical considerations which are useful to inform development of new models.

Background: Comparative analyses of published cost effectiveness models provide useful insights into critical issues to inform the development of new cost effectiveness models in the same disease area.Objective: The purpose of this study was to describe a comparative analysis of cost-effectiveness models and highlight the importance of such work in informing development of new models. This research uses genotypic antiretroviral resistance testing after first line treatment failure for Human Immunodeficiency Virus (HIV) as an example.Method: A literature search was performed, and published cost effectiveness models were selected according to predetermined eligibility criteria. A comprehensive comparative analysis was undertaken for all aspects of the models.Results: Five published models were compared, and several critical issues were identified for consideration when developing a new model. These include the comparator, time horizon and scope of the model. In addition, the composite effect of drug resistance prevalence, antiretroviral therapy efficacy, test performance and the proportion of patients switching to second-line ART potentially have a measurable effect on model results. When considering CD4 count and viral load, dichotomizing patients according to higher cost and lower quality of life (AIDS) versus lower cost and higher quality of life (non-AIDS) status will potentially capture differences between resistance testing and other strategies, which could be confirmed by cross-validation/convergent validation. A quality adjusted life year is an essential outcome which should be explicitly explored in probabilistic sensitivity analysis, where possible.Conclusions: Using an example of GART for HIV, this study demonstrates comparative analysis of previously published cost effectiveness models yields critical information which can be used to inform the structure and specifications of new models.

Speeding up the study of diluted dipolar systems.

We study the regimes of a diluted dipolar system through Monte Carlo numerical simulations in the NVT ensemble. To accelerate the dynamics, several approximations and speed-up algorithms are proposed and tested. In particular, it turns out that "cluster move Monte Carlo" algorithm speeds-up to two decades faster than the traditional Monte Carlo, depending on temperature and density. We find simple-fluid, chain-fluid, ring-fluid, gel, and antiparallel columnar regimes, which are studied and characterized through positional, orientational, and thermodynamical observables.

Depression and all-cause mortality risk in HIV-infected and HIV-uninfected US veterans: a cohort study.

OBJECTIVES: The contribution of depression to mortality in adults with and without HIV infection is unclear. We hypothesized that depression increases mortality risk and that this association is stronger among those with HIV infection. METHODS: Veterans Aging Cohort Study (VACS) data were analysed from the first clinic visit on or after 1 April 2003 (baseline) to 30 September 2015. Depression definitions were: (1) major depressive disorder defined using International Classification of Diseases, Ninth Revision (ICD-9) codes; (2) depressive symptoms defined as Patient Health Questionnaire (PHQ)-9 scores ≥ 10. The outcome was all-cause mortality. Covariates were demographics, comorbid conditions and health behaviours. RESULTS: Among 129 140 eligible participants, 30% had HIV infection, 16% had a major depressive disorder diagnosis, and 24% died over a median follow-up time of 11 years. The death rate was 25.3 [95% confidence interval (CI) 25.0-25.6] deaths per 1000 person-years. Major depressive disorder was associated with mortality [hazard ratio (HR) 1.04; 95% CI 1.01, 1.07]. This association was modified by HIV status (interaction P-value = 0.02). In HIV-stratified analyses, depression was significantly associated with mortality among HIV-uninfected veterans but not among those with HIV infection. Among those with PHQ-9 data (n = 7372), 50% had HIV infection, 22% had PHQ-9 scores ≥ 10, and 28% died over a median follow-up time of 12 years. The death rate was 27.3 (95% CI 26.1-28.5) per 1000 person-years. Depressive symptoms were associated with mortality (HR 1.16; 95% CI 1.04, 1.28). This association was modified by HIV status (interaction P-value = 0.05). In HIV-stratified analyses, depressive symptoms were significantly associated with mortality among veterans with HIV infection but not among those without HIV infection. CONCLUSIONS: Depression was associated with all-cause mortality. This association was modified by HIV status and method of depression ascertainment.

Targeting the third '90': introducing the viral load champion.

Objective: To move closer to achieving the third target of the UNAIDS 90-90-90 goals, we prospectively implemented a viral load (VL) champion (VLC) program aimed at enhancing VL monitoring and recognition of treatment failure. Design: Three clinics in eThekwini, Kwa-Zulu Natal (low-, medium- and high-volume, encompassing 9184 patients overall) were each assigned a VLC. We employed a descriptive analysis (chart audit) to compare the pre-intervention period to a 1-year post-intervention period. The number of patients with a VL test performed 6 and 12 months after the intervention was calculated as a proportion of VL tests due at those time points (VL completion rate). Results: The pre-implementation VL completion rate at the three sites was respectively 68% (140/205 patients), 54% (84/155 patients) and 64% (323/504 patients), and the 6-month post-implementation completion rate increased to 83% (995/1194 patients), 90% (793/878 patients) and 99% (3101/3124 patients) (P < 0.0001 for each site). VL completion rates remained significantly higher at 12 months post-implementation, with an average cumulative VL completion rate of >90% across all facilities. Conclusion: We demonstrate a successful, multifaceted, quality-improvement intervention centered on a clinic-level VLC which, taken to scale, has important implications for attaining the third UNAIDS 90-90-90 target.

Objectif : Dans le but de se rapprocher de l'atteinte de la troisième cible des objectifs 90-90-90 du Programme commun des Nations Unies sur le VIH/Sida (ONUSIDA), nous avons prospectivement mis en œuvre un programme « champion de la charge virale ¼ (VLC) visant à améliorer le suivi de la charge virale (VL) et la reconnaissance de l'échec du traitement.Schéma : Trois centres à eThekwini, Kwa-Zulu Natal (volume faible, moyen et élevé, soit 9184 patients au total), ont été chacun affectés au VLC. Nous employons une analyse descriptive (audit de dossiers) afin de comparer la période avant l'intervention à la période d'un an qui a suivi l'intervention. Le nombre de patients ayant eu un test VL 6 et 12 mois après l'intervention a été calculé comme une proportion de test VL exigibles à ces dates respectivement (taux d'achèvement du VL).Résultats : Le taux d'achèvement du VL avant la mise en route dans trois sites a été de 68% (140/205 patients), 54% (84/155 patients) et 64% (323/504 patients), respectivement, et le taux d'achèvement à 6 mois après la mise en œuvre a augmenté à 83% (995/1194 patients), 90% (793/878 patients) et 99% (3101/3124 patients), respectivement (P < 0,0001 pour chaque site). Les taux d'achèvement du VL sont restés significativement plus élevés à 12 mois après la mise en œuvre, avec un taux cumulé moyen du VL >90% dans toutes les structures.Conclusion : Nous avons montré la qualité d'une intervention d'amélioration réussie à multiples facettes, centrée sur le VLC au niveau des centres qui­à plus grande échelle­a des implications majeures pour l'atteinte de la troisième cible 90-90-90 de l'ONUSIDA.

Objetivo: Con el propósito de avanzar hacia el cumplimiento del tercer elemento del objetivo «90-90-90¼ del Programa Conjunto de las Naciones Unidas sobre el VIH/SIDA (ONUSIDA), se introdujo un programa con un promotor del seguimiento de la viremia, encaminado a reforzar la vigilancia de la concentración vírica y el reconocimiento del fracaso terapéutico.Método: En cada uno de tres consultorios de eThekwini, en Kwa-Zulu Natal (con una carga asistencial baja, intermedia y alta, que cubrían un total de 9184 pacientes) se nombró un promotor del seguimiento de la viremia. Mediante un análisis descriptivo, se comparó el período preintervención con un período posintervención de un año. El número de pacientes en quienes se practicó la viremia a los 6 y 12 meses después de la intervención se calculó como la proporción de las viremias previstas en estos puntos temporales (tasa de compleción de la viremia).Resultados: La tasa de compleción de la viremia en los tres centros fue como sigue: 68% (140/205 pacientes), 54% (84/155 pacientes) y 64% (323/504 pacientes) y a los 6 meses posintervención, esta tasa aumentó respectivamente a 83% (995/1194 pacientes), 90% (793/878 pacientes) y 99% (3101/3124 pacientes) (P < 0,0001 para cada centro). Las tasas de compleción de la viremia permanecieron significativamente más altas a los 12 meses posintervención con una tasa acumulada superior al 90% en todos los establecimientos.Conclusión: Se puso en evidencia una intervención polifacética eficaz de mejoramiento de la calidad centrada en un promotor clínico del seguimiento de la viremia en cada consultorio, cuya aplicación en una escala más amplia, tendría importantes repercusiones en favor del cumplimiento del tercer elemento del objetivo «90-90-90¼ del ONUSIDA.

Disrupting the wall accumulation of human sperm cells by artificial corrugation.

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells ∼60 µm long, strongly confined to ∼25 µm shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.

PC1, a non-peptide PKR1-preferring antagonist, reduces pain behavior and spinal neuronal sensitization in neuropathic mice.

Peripheral neuropathy is characterized by abnormal pain responses triggered by the release of several mediators and neuronal hyperexcitability at the spinal cord level. Emerging evidence indicates that the enhanced activity of dorsal horn neurons requires communication with glia and microglia, cells that are physiologically involved in neuronal wellbeing. Prokineticins (PKs), which include PK1 and PK2, represent a novel family of chemokines characterized by a unique structural motif comprising five disulfide bonds. They are expressed in the peripheral and central nervous system. PKs bind two G protein coupled receptors, PKR1 and PKR2, and participate in the regulation of several biological processes, including pain sensation. This study aimed to investigate the anti-nociceptive effect of PC1, a non-peptide PKR1-preferring antagonist, in a mouse model of neuropathic pain. To do this, we assessed the activity of spinal cord nociceptive neurons as well as astrocyte and microglia phenotypes after repeated administration of PC1 in vivo. PC1 treatment strongly delayed the development of thermal hyperalgesia and tactile and mechanical allodynia. It also reduced spinal microglial and glial activation 8 days post injury in spared nerve injury (SNI) mice. Neuropathic mice showed an increased level of PK2 protein in the spinal cord, mostly in astrocytes. PC1 treatment completely reversed the increased responsiveness to mechanical stimuli, the decreased threshold of neuronal activation, and the increased spontaneous activity that were observed in nociceptive specific (NS) neurons of SNI mice.

Controlling the activation of the Bv8/prokineticin system reduces neuroinflammation and abolishes thermal and tactile hyperalgesia in neuropathic animals.

BACKGROUND AND PURPOSE: Chemokines are involved in neuroinflammation and contribute to chronic pain processing. The new chemokine prokineticin 2 (PROK2) and its receptors (PKR1 and PKR2 ) have a role in inflammatory pain and immunomodulation. In the present study, we investigated the involvement of PROK2 and its receptors in neuropathic pain. EXPERIMENTAL APPROACH: Effects of single, intrathecal, perineural and s.c. injections of the PKR antagonist PC1, or of 1 week s.c. treatment, on thermal hyperalgesia and tactile allodynia was evaluated in mice with chronic constriction of the sciatic nerve (CCI). Expression and localization of PROK2 and of its receptors at peripheral and central level was evaluated 10 days after CCI, following treatment for 1 week with saline or PC1. IL-1ß and IL-10 levels, along with glia activation, were evaluated. KEY RESULTS: Subcutaneous, intrathecal and perineural PC1 acutely abolished the CCI-induced hyperalgesia and allodynia. At 10 days after CCI, PROK2 and its receptor PKR2 were up-regulated in nociceptors, in Schwann cells and in activated astrocytes of the spinal cord. Therapeutic treatment with PC1 (s.c., 1 week) alleviated established thermal hyperalgesia and allodynia, reduced the injury-induced overexpression of PROK2, significantly blunted nerve injury-induced microgliosis and astrocyte activation in the spinal cord and restored the physiological levels of proinflammatory and anti-inflammatory cytokines in periphery and in spinal cord. CONCLUSION AND IMPLICATIONS: The prokineticin system contributes to pain modulation via neuron-glia interaction. Sustained inhibition of the prokineticin system, at peripheral or central levels, blocked both pain symptoms and some events underlying disease progression.

Geometrical guidance and trapping transition of human sperm cells.

The guidance of human sperm cells under confinement in quasi-2D microchambers is investigated using a purely physical method to control their distribution. Transport property measurements and simulations are performed with diluted sperm populations, for which effects of geometrical guidance and concentration are studied in detail. In particular, a trapping transition at convex angular wall features is identified and analyzed. We also show that highly efficient microratchets can be fabricated by using curved asymmetric obstacles to take advantage of the spermatozoa specific swimming strategy.

Botanicals in Ribes nigrum bud-preparations: an analytical fingerprinting to evaluate the bioactive contribution to total phytocomplex.

UNLABELLED: CONTEXT. Ribes nigrum L. (Grossulariaceae) is among the most commonly used herbal medicines and it is popularized for its alleged tonic effect and curative and restorative properties. The current practice of identifying herbal extracts is by measuring the concentration of the main botanicals. Their concentrations are used to characterize the herbal preparations and fingerprinting is recommended by the main Pharmacopeias as a potential and reliable strategy for the quality control of complex mixtures. OBJECTIVE: The aim of this research was to perform an analytical study of R. nigrum bud-preparations, in order to identify and quantify the main bioactive compounds, obtaining a specific chemical fingerprint to evaluate the single class contribution to herbal preparation phytocomplex. MATERIALS AND METHODS: The same analyses were performed using a high-performance liquid chromatograph-diode array detector both on University lab preparations and on commercial preparations from different Italian locations. Different chromatographic methods were used to analyse the macerated samples, two for polyphenols and one for terpenic compounds. RESULTS. Ribes nigrum was identified as a rich source of anti-inflammatory and antioxidant compounds. The observed analytical firgerprint demonstrated that these bud-preparations represent a rich source of terpenic and polyphenolic compounds, especially catechins and phenolic acids. DISCUSSION AND CONCLUSION: Analytical fingerprinting could be an important tool to study the assessment of chemical composition and bioactivities of plant-derived products, helping to find new sources of natural health-promoting compounds: this study allowed the development of an effective tool for quality control through botanical fingerprinting of bud preparations.

Influence of swimming strategy on microorganism separation by asymmetric obstacles.

It has been shown that a nanoliter chamber separated by a wall of asymmetric obstacles can lead to an inhomogeneous distribution of self-propelled microorganisms. Although it is well established that this rectification effect arises from the interaction between the swimmers and the noncentrosymmetric pillars, here we demonstrate numerically that its efficiency is strongly dependent on the detailed dynamics of the individual microorganism. In particular, for the case of run-and-tumble dynamics, the distribution of run lengths, the rotational diffusion, and the partial preservation of run orientation memory through a tumble are important factors when computing the rectification efficiency. In addition, we optimize the geometrical dimensions of the asymmetric pillars in order to maximize the swimmer concentration and we illustrate how it can be used for sorting by swimming strategy in a long array of parallel obstacles.

The Locomotory Index in diplegic and hemiplegic children: the effects of age and speed on the energy cost of walking.

BACKGROUND: The energy cost of locomotion (C) is a useful tool for quantifying the level of walking disability in the clinical evaluation of patients with cerebral palsy (CP). In addition to clinical condition, also age and velocity (v) can influence C, a fact that is often overlooked. AIM: To show: i) that C differs in the clinical subtypes of CP (hemiplegia or diplegia) and ii) that C should be measured at comparable speeds in CP patients and controls (of the same age). DESIGN: Controlled study. SETTING: Pediatric Rehabilitation Unit of "E. Medea" Scientific Institute (Conegliano, TV); Exercise Physiology Lab of University of Verona. POPULATION: Forty-three CP children (32 diplegic: Dg; 11 hemiplegic: Hg) and 20 healthy children (Cg) with an age range of 4-14 years. METHODS: C was measured as the ratio of net oxygen uptake to walking speed (at v from 1 to 6 km·h(-1)). The Locomotory index (LI) was calculated as the ratio of C in Dg/Hg and Cg (of the same age) at the same speed. RESULTS: C decreases with increasing speed in all groups but evolves differently in Hg and Dg: in the former C decreases by increasing age, becoming similar to that of Cg at 12-14 years; in the latter C does not change as a function of age being always larger than in Cg. CONCLUSION AND CLINICAL REHABILITATION IMPACT: Our data highlight the reduction in C with increasing speed and suggest a better prognosis of locomotion for Hg compared to Dg.

Applicability of a new robotic walking aid in a patient with cerebral palsy. Case report.

BACKGROUND: Gait training with the help of assistive technological devices is an innovative field of research in neurological rehabilitation. Most of the available gait training devices do not allow free movement in the environment, which would be the most suitable natural and motivating condition for training children with neurological gait impairment. AIM: To evaluate the potential applicability of a new robotic walking aid as a tool for gait training in non-ambulatory children with Cerebral Palsy. DESIGN: Single case study SETTING: Outpatient regimen POPULATION: A 11-years-old child unable to stand and walk independently as a result of spastic tetraplegic cerebral palsy (CP). METHODS: The experimental device was a newly actuated version of a dynamic combined walking and standing aid (NF-Walker®) available in the market which was modified by means of two pneumatic artificial muscles driven by a foot-switch inserted in the shoes. The child was tested at baseline (while maintaining the standing position aided by the non-actuated NF-Walker®) and in the experimental condition (while using the actuated robotic aid). The outcome measures were: 2-minute walking test, 10-metre walking test, respiratory and heart parameters, energy cost of locomotion. RESULTS: At baseline, the child was unable to perform any autonomous form of locomotion. When assisted by the actuated aid (i.e. during the experimental condition), the child was successful in moving around in his environment. His performance was 19.63 m in the 2-minute walking test and 64 s in the 10-metre walking test. Respiratory and heart parameters were higher than healthy age-matched children both at baseline and in the experimental condition. The energy cost of gait, which was not valuable in the baseline condition, was significantly higher than normality during the experimental condition. CONCLUSION: The new robotic walking aid may help children suffering from CP with severe impairment of gait to move around in their environment. CLINICAL REHABILITATION IMPACT: This new robotic walking device may have a potential impact in stimulating the development and in training of gait in children with neurological gait impairment. Future studies are warranted in order to test this hypothesis.

Improved VO2 uptake kinetics and shift in muscle fiber type in high-altitude trekkers.

The study investigated the effect of prolonged hypoxia on central [i.e., cardiovascular oxygen delivery (Q(a)O(2))] and peripheral (i.e., O(2) utilization) determinants of oxidative metabolism response during exercise in humans. To this aim, seven male mountaineers were examined before and immediately after the Himalayan Expedition Interamnia 8000-Manaslu 2008, lasting 43 days, among which, 23 days were above 5,000 m. The subjects showed a decrease in body weight (P < 0.05) and of power output during a Wingate Anaerobic test (P < 0.05) and an increase of thigh cross-sectional area (P < 0.05). Absolute maximal O(2) uptake (VO(2max)) did not change. The mean response time of VO(2) kinetics at the onset of step submaximal cycling exercise was reduced significantly from 53.8 s ± 10.9 to 39.8 s ± 10.9 (P < 0.05), whereas that of Q(a)O(2) was not. Analysis of single fibers dissected from vastus lateralis biopsies revealed that the expression of slow isoforms of both heavy and light myosin subunits increased, whereas that of fast isoforms decreased. Unloaded shortening velocity of fibers was decreased significantly. In summary, independent findings converge in indicating that adaptation to chronic hypoxia brings about a fast-to-slow transition of muscle fibers, resulting in a faster activation of the mitochondrial oxidative metabolism. These results indicate that a prolonged and active sojourn in hypoxia may induce muscular ultrastructural and functional changes similar to those observed after aerobic training.

Crossed-ratchet effects for magnetic domain wall motion.

We study both experimentally and theoretically the driven motion of domain walls in extended amorphous magnetic films patterned with a periodic array of asymmetric holes. We find two crossed-ratchet effects of opposite sign that change the preferred sense for domain wall propagation, depending on whether a flat or a kinked wall is moving. By solving numerically a simple phi(4) model we show that the essential physical ingredients for this effect are quite generic and could be realized in other experimental systems involving elastic interfaces moving in multidimensional ratchet potentials.

Diffuse interface approach to brittle fracture.

We present a continuum model for the propagation of cracks and fractures in brittle materials. The components of the strain tensor epsilon are the fundamental variables. The evolution equations are based on a free energy that reduces to that of linear elasticity for small epsilon, and accounts for cracks through energy saturation at large values of epsilon. We regularize the model by including terms dependent on gradients of epsilon in the free energy. No additional fields are introduced, and then the whole dynamics is perfectly defined. We show that the model is able to reproduce basic facts in fracture physics, like the Griffith's dependence of the critical stress as a minus one-half power of the crack length. In addition, regularization makes the results insensitive to the numerical mesh used, something not at all trivial in crack modeling. We present an example of the application of the model to predict the growth and curving of cracks in a nontrivial geometrical configuration.